Currently, you can only do it through an ODS style. You can create a small style that inherits from the style you're using but only adjusts the datalabel font size. Here is an example:
Hi,
I tried this solution for a similar problem but it dosn't work for me.
I would like to increase the resolution of my graph-output. Therefor, I increased width and hight in the ods graphics statement. Unfortunately the font size stayed at the same size.
It would be nice, if someone could help my finding a way to get a bigger font size!
If the goal is to increase the graph resolution, use the IMAGE_DPI option on the ODS destination statement (for PRINTER or PDF, use the DPI option). If you are trying to do this with HTML output, I have found that browsers do not typically handle images higher than 100dpi very well. Let me know if this works out for you.